Cupola with forehearth



Aug. 14, 1928.

- H. LUYKEN CUPOLA WITH 'FORE HEARTH Filed Feb. 26,- 1924 [n rentor' M$1 M:

Patented Au 14, 1928.

UNITED STATES HUGO LUYKEN, 0F BIELEFELD, GERMANY.

CUPOLA WITH FOREHEAR'IH.

Application filed February 26, 1924, Serial No. 695,259, and in GermanyMarch 5, 1923.

In order to utilize the molten iron from a cupola to the best advantage,it is necessary to have it as free from slag as possible, otherwise slagis likely to enter the mold with the iron and thus ruin the casting. Itis particularly necessary to keep slag away from molten iron which is tobe subjected to chemical action to refine it, as otherwise thispurification of the metal is injuriously affected, if not preventedaltogether. This condition is very marked in the case of thedesulphurization process by means of alkalics.

In order that molten iron free from slag may be taken from a cupola itis not sufficient, as has been hitherto proposed, to provide the cupolawith an overflow discharge channel even if the level of the overflow andconsequently also that of the metal within the cupola is kept fairlyhigh over the discharge opening at the bottom of the cupola.

Experience has shown that in spite of such overflow channel undercertain conditions which are out of control of the operator the slagfinds its way to the overflow. The purpose of this invention is toovercome this difliculty and the desired eflect is secured by throttlingthe stream of molten metal in its flow from the cupola to the overflowchannel. Although this throttling action does not affect the equilibriumbetween the column of molten metal within the overflow channel and thecolumn of molten metal,

its slag layer and the blast pressure within the cupola, neverthelessthe throttle prevents occasional fluctuations in pressure occurringduring the run of the cupola from forcing slag from the cupola to theoverflow. The action of the contraction in the discharge channel forthrottling purposes is further enhanced if the cross section of theuprightovorflow channel is considerably enlarged compared with thethrott-led connecting channel leading from the cupola to the saidupright overflow channel.

The invention is illustrated on the accompanying drawing which shows oneform of cupola with fore-hearth or ladle connected with the cupola by aninterposed upright overflow channel with a throttled feed branch at itslower end.

The cupola shaft is designated a, the forehoarth Z), the contractedconnecting channel 0, the upright comparatively wide overflow channel(5, and the channel for the overflow at the upper end of channel orchamberd is designated 6. The bridge, over which the iron flows isdesignated 9. The reference character f designates an opening in theside of the fore-hearth, which serves to allow the introduction ofrefining materials, as for instance a 'desulphurizing material. Anopening It in the shell of the cupola serves to draw off the slag fromwithin.

The cupola-shaft and the fore-hearth, together with the connectingchannels 0, d, 0 form a set of communicating pipes which allow themolten metal in the cupola coming from the material charged to act inaccordance with the laws governing the flow of liquids in pipes.

The contracted channel 0, however, we vents any cumulative forces causedby pressure fluctuations within the cupola from becoming effectivewithin the pipe system, and thus effectively prevents possibledepressions in the slag level within the cupola which would force slagthrough the channel 0, and into the fore-hearth by way of the uprightchamber d.

WVhat I claim is:

In a furnace comprising a cupola and a fore-hearth, a verticallyextending channel having the upper end thereof in open communicationwith the upper portion of said. fore-hearth, and a passage of restrictedcross-section between the lower end of said channel and the shaft ofsaid cupola, whereby momentary fluctuations of the level of the moltenmetal in said cupola shaft are damped In testimony whereof, I aflix mysignature.

HUGO LUYKEN.

